Name

Synopsis

Description

The /etc/shorewall6/zones file declares your network zones. You specify the hosts in each zone through entries in
/etc/shorewall6/interfaces or
/etc/shorewall6/hosts.

The columns in the file are as follows (where the column name is
followed by a different name in parentheses, the different name is used in
the alternate specification syntax).

ZONE -
zone[:parent-zone[,parent-zone]...]

Name of the zone. The names "all",
"none", "SOURCE" and "DEST" are reserved and may not be used as zone
names. The maximum length of a zone name is determined by the
setting of the LOGFORMAT option in shorewall6.conf(5).
With the default LOGFORMAT, zone names can be at most 5 characters
long.

The maximum length of an iptables log prefix is 29 bytes. As
explained in shorewall6.conf (5),
the default LOGPREFIX formatting string is “Shorewall:%s:%s:”
where the first %s is replaced by the chain name and the second is
replaced by the disposition.

The default formatting string has 12 fixed characters
("Shorewall" and three colons).

The longest of the standard dispositions are ACCEPT and
REJECT which have 6 characters each.

The canonical name for the chain containing the rules
for traffic going from zone 1 to zone 2 is "<zone
1>2<zone 2>".

So if M is the maximum zone name length, such chains can
have length 2*M + 1.

12 + 6 + 2*M + 1 = 29 which reduces to

2*M = 29 - 12 - 6 - 1 = 10 or

M = 5

The order in which Shorewall6 matches addresses from packets
to zones is determined by the order of zone declarations. Where a
zone is nested in one or more other zones, you may either ensure
that the nested zone precedes its parents in this file, or you may
follow the (sub)zone name by ":" and a comma-separated list of the
parent zones. The parent zones must have been declared in earlier
records in this file. See shorewall6-nesting(5)
for additional information.

Example:

#ZONE TYPE OPTIONS IN OPTIONS OUT OPTIONS
a ipv6
b ipv6
c:a,b ipv6

Currently, Shorewall6 uses this information to reorder the
zone list so that parent zones appear after their subzones in the
list. The IMPLICIT_CONTINUE option in shorewall6.conf(5) can
also create implicit CONTINUE policies to/from the subzone.

Where an ipsec zone is
explicitly included as a child of an ipv6 zone, the ruleset allows CONTINUE
policies (explicit or implicit) to work as expected.

In the future, Shorewall6 may make additional use of nesting
information.

TYPE

ipv6

This is the standard Shorewall6 zone type and is the
default if you leave this column empty or if you enter "-" in
the column. Communication with some zone hosts may be
encrypted. Encrypted hosts are designated using the 'ipsec'
option in shorewall6-hosts(5).

ipsec (or ipsec6)

Communication with all zone hosts is encrypted. Your
kernel and ip6tables must include policy match support.

firewall

Designates the firewall itself. You must have exactly
one 'firewall' zone. No options are permitted with a
'firewall' zone. The name that you enter in the ZONE column
will be stored in the shell variable $FW which you may use in
other configuration files to designate the firewall
zone.

bport (or bport6)

The zone is associated with one or more ports on a
single bridge.

vserver

Added in Shorewall 4.4.11 Beta 2 - A zone composed of
Linux-vserver guests. The zone contents must be defined in
shorewall6-hosts
(5).

Vserver zones are implicitly handled as subzones of the
firewall zone.

loopback

Added in Shorewall 4.5.17.

Normally, Shorewall treats the loopback interface (lo)
in the following way:

By default, all traffic through the interface is
ACCEPTed.

If a $FW -> $FW policy is defined or $FW ->
$FW rules are defined, they are placed in a chain named
${FW}2${F2} or ${FW}-${FW} (e.g., 'fw2fw' or 'fw-fw' )
depending on the ZONE2ZONE setting in shorewall6.conf(5).

$FW -> $FW traffic is only filtered in the OUTPUT
chain.

By defining a loopback
zone and associating it with the loopback interface in
shorewall-interfaces(5), you can effect a slightly different
model. Suppose that the loopback zone name is 'local';
then:

Both $FW -> local and local -> $FW chains are
created.

The $FW -> local and local -> $FW policies may
be different.

Both $FW -> local and local -> $FW rules may
be specified.

Rules to/from the loopback zone and any zone other than
the firewall zone are ignored with a warning.

loopback zones may be
nested within other loopback
zones.

local

Added in Shorewall 4.5.17. local is the same as ipv6 with the exception that the zone
is only accessible from the firewall and vserver zones.

A comma-separated list of options. With the exception of the
mss and blacklist options, these
only apply to TYPE ipsec zones.

blacklist

Added in Shorewall 4.4.13. May not be specified for
firewall or vserver zones.

When specified in the IN_OPTIONS column, causes all
traffic from this zone to be passed against the src entries in shorewall6-blacklist(5).

When specified in the OUT_OPTIONS column, causes all
traffic to this zone to be passed against the dst entries in shorewall6-blacklist(5).

Specifying this option in the OPTIONS column is
equivalent to entering it in both of the IN_OPTIONS and
OUT_OPTIONS column.

dynamic_shared

Added in Shorewall 4.5.9. May only be specified in the
OPTIONS column and indicates that only a single ipset should
be created for this zone if it has multiple dynamic entries in
shorewall6-hosts(5).
Without this option, a separate ipset is created for each
interface.

reqid=number

where number is specified using
setkey(8) using the 'unique:number option
for the SPD level.

spi=<number>

where number is the SPI of the SA
used to encrypt/decrypt packets.

proto=ah|esp|ipcomp

IPSEC Encapsulation Protocol

mss=number

sets the MSS field in TCP packets. If you supply this
option, you should also set FASTACCEPT=No in shorewall6.conf(5)
to insure that both the SYN and SYN,ACK packets have their MSS
field adjusted.

mode=transport|tunnel

IPSEC mode

tunnel-src=address[/mask]

only available with mode=tunnel

tunnel-dst=address[/mask]

only available with mode=tunnel

strict

Means that packets must match all rules.

next

Separates rules; can only be used with strict

The options in the OPTIONS column are applied to both incoming
and outgoing traffic. The IN OPTIONS are applied to incoming traffic
(in addition to OPTIONS) and the OUT OPTIONS are applied to outgoing
traffic.

If you wish to leave a column empty but need to make an entry
in a following column, use "-".